Matthias Hamann

Teaching

• Vorlesung Gruppentheorie


• frühere Lehre

Publications

• The planar Cayley graphs are effectively enumerable II (joint with A. Georgakopoulos), European Journal of Combinatorics 110 (2023), Paper No. 103668
• A Stallings type theorem for quasi-transitive graphs (joint with F. Lehner, B. Miraftab & T. Rühmann), Journal of Combinatorial Theory (Series B) 157 (2022), 40-69
• Canonical trees of tree-decompositions (joint with J. Carmesin & B. Miraftab), Journal of Combinatorial Theory (Series B) 152 (2022), 1-26
• The planar Cayley graphs are effectively enumerable I: consistently planar graphs (joint with A. Georgakopoulos), Combinatorica 39 (2019), 993-1019
• Self-embeddings of trees, Discrete Mathematics 342 (2019), 111586
• Planar transitive graphs, Electronic Journal of Combinatorics 25 (2018), Paper 4.8
• Accessibility in transitive graphs, Combinatorica 38 (2018), 847-859
• On the tree-likeness of hyperbolic spaces, Math. Proc. Cambridge Philos. Soc. 164 (2018), 345-361
• The classification of finite and locally finite connected-homogeneous digraphs, Combinatorica 37 (2017), 183-222
• Bounding connected tree-width (joint with D. Weißauer), SIAM Journal on Discrete Mathematics 30 (2016), 1391-1400
• Groups acting on metric spaces: fixed points and free subgroups, Abhandlungen des Mathematischen Seminars der Universität Hamburg 87 (Special Issue: Rudolf Halin) (2017), 245-263
• Extending cycles locally to Hamilton cycles (joint with F. Lehner & J. Pott), Electronic Journal of Combinatorics 23 (2016), Paper 1.49
• Canonical tree-decompositions of finite graphs II. Essential parts (joint with J. Carmesin, R. Diestel & F. Hundertmark), Journal of Combinatorial Theory (Series B) 118 (2016), 268-283
• Canonical tree-decompositions of finite graphs I. Existence and algorithms (joint with J. Carmesin, R. Diestel & F. Hundertmark), Journal of Combinatorial Theory (Series B) 116 (2016), 1-24
• Spanning trees in hyperbolic graphs, Combinatorica 36 (2016), 313-332
• Generating the cycle space of planar graphs, Electronic Journal of Combinatorics 22 (2015), Paper 2.34
• k-Blocks: a connectivity invariant for graphs (joint with J. Carmesin, R. Diestel & F. Hundertmark), SIAM Journal on Discrete Mathematics 28 (2014), 1876-1891
  extended version
• Homogeneous 2-partite digraphs, Discrete Mathematics 327 (2014), 36-39
• The classification of connected-homogeneous digraphs with more than one end (joint with F. Hundertmark), Transactions of the AMS 365 (2013), 531-553
• Transitivity conditions in infinite graphs (joint with J. Pott), Combinatorica 32 (2012), 649-688
• On fixing boundary points of transitive hyperbolic graphs (joint with A. Georgakopoulos), Archiv der Mathematik 99 (2012), 91-99
• End-transitive graphs, Israel Journal of Mathematics 189 (2012), 437-459

Preprints

• Countable connected-homogeneous digraphs, submitted
• Tree amalgamations and quasi-isometries, submitted
• Tree amalgamations and hyperbolic boundaries, submitted
• Asymptotic dimension of multi-ended quasi-transitive graphs, submitted
• Two characterisations of accessible quasi-transitive graphs (joint with B. Miraftab), submitted
• Hyperbolicity in semimetric spaces, digraphs and semigroups, submitted
• Minor exclusion in quasi-transitive graphs, submitted

Theses

• Connected-homogeneous digraphs, Habilitationsschrift, University of Hamburg, Department of Mathematics, September 2014
• Infinite graphs with a treelike structure, PhD Thesis, University of Hamburg, Department of Mathematics, June 2011
• Über die lokale Struktur endlicher Gruppen lokaler Charakteristik p vom Rang 2, Diplomarbeit, Christian-Albrechts-Universität zu Kiel, Mathematisches Seminar, October 2007